Replacing single H4 55 bulb with twin H4 35 to prevent drain

wayland · L Plate Warrior Joined: 02 May 2010 Karma :

Hi, I've had a twin headlight conversion from a single H4 55/60watt bulb to two 55w. The bike (bandit 600) has been coping well for well over a year but recently seems to fail to charge the battery up fully (I do use the lights almost permanently safety reasons and commuting so lots of night driving).

So, would it be possible to replace the two 55w bulbs with 35w bulbs or would they just burn out? Also, would there be a noticable loss in illumination?

Has anyone tried this, or does anyone know enough about this to comment?

Thanks

Davo · Davo To The Rescue! Joined: 04 Apr 2004 Karma :

Putting two 35w bulbs in shouldn't cause them to burn out

My friend did a similar conversion on his Bandit 600, the bulbs that came with the kit were only 35w.

I borrowed his bike a couple of weeks later, and whilst fine for daylight use, riding in the dark was bloody dangerous, it felt like I was riding on sidelights.

As another thought could you not wire up the headlights so that only one is on, then have a switched relay to switch both lights on (like some of the newer sports bikes)? (not sure about the legality of this though)

I personally don't run with headlights on during the day unless conditions necessitate them, as I don't consider daylight headlights to be any safer.

wayland · L Plate Warrior Joined: 02 May 2010 Karma :

Cheers. I was afraid that might be the case. I read somewhere that a bulb that doesn't get a 100% current is darker than one that is rated lower but get its full current... Guess it was wishful thinking on my part. Although I have to say, IMHO, that the lights on the bandit (MK1) leave lots to be desired anyway, which is why i installed the twins.

The one-on-one-off set-up sounds like the way forward... now I'm wondering if it would blow a single 35W if i'd use it as the day light.

Thanks for the comment. Saved me £20!

MarkJ · World Chat Champion Joined: 11 Apr 2006 Karma :

What about a single 35w HID kit?

herulach · World Chat Champion Joined: 19 Apr 2010 Karma :

Don't get a HID kit, it will screw the beam up something chronic, and won't pass an MOT (assuming bike MOTs test for headlight cutoff like car ones do)

Rather than wire them one on one off, try wiring it so the bulbs are in series for DRL then switch back to parallel for night riding. THat way you'll get about the same (admittedly pretty yellow) light as one bulb during the day, whilst still keeping both lit. (IMO twin headlamps with only 1 lit look pretty daft.)